Technical considerations in the delivery of the kidney during laparoscopic live-donor nephrectomy.
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Humans↗
Biomedical subjects
L R Kavoussi
Publications and source records attributed to L R Kavoussi.
Secure transmission of urologic images and records over the Internet.
PURPOSE: Telemedicine has become a common method for the transmission of images and patient data across long distances. Our goal was to assess the efficiency and accuracy of Photomailer MD software, a store-and-forward telemedicine system, in the urologic setting. METHODS: Photomailer MD software was loaded on two computers in the host institution, one with a T1 connection to the Internet and the other with a dial-up modem connection (24,000 bits/second), and computers at three remote sites. A total of 14 clinical cases, comprised of digitized histories and radiographic images, were sent to the remote institutions four separate times using the four transmission modes available: nonencrypted, 56-bit encryption, 128-bit encryption, and 128-bit encryption with password. The following data points were recorded: file size before and after encryption, file transmission times, and diagnostic accuracy of the remote urologists. One-way ANOVA was used to compare mean values statistically, while the z-test was used to compare diagnostic accuracies. RESULTS: Encryption increased the file size by a mean of 37.8%, with the three encryption modes increasing file sizes by the same number of kilobytes. When a dial-up modem was used, encrypted files required a significantly longer transmission time (P < 0.05) than the unencrypted files. The same trend was seen with the T1 connection, although the differences often were not significant. When T1 transmission times were compared with modem times with other variables held constant, modem times were significantly longer (P < 0.05). Diagnostic accuracies for each of the three remote centers ranged from 85.7% to 100%. Differences in accuracy rates between attending physicians and residents were not significant. CONCLUSIONS: Photomailer MD provides a secure, convenient, and affordable method of transmitting patient images and records via the Internet. Transmission speed was significantly greater when using a T1 line and also tended to be faster when files were not encrypted. There was no significant difference in transmission time among the three encryption modes; therefore, 128-bit encryption with a password should be used to maximize security. Diagnostic accuracies were comparable to those in the literature. In general, 640 x 480-pixel resolution was adequate for urologic diagnoses, although higher-resolution images may improve accuracy.
Analysis of Variance↗
Laparoscopic renal cryoablation: acute and long-term clinical, radiographic, and pathologic effects in an animal model and application in a clinical trial.
OBJECTIVES: To evaluate renal cryosurgery by studying the feasibility of laparoscopic delivery and the radiographic characteristics and histopathologic effects in a porcine model using different freeze cycles. On the basis of the results, a clinical trial of laparoscopic cryosurgical ablation in select patients with clinical stage T1 renal tumors was started. MATERIALS AND METHODS: Twelve kidneys from six farm pigs underwent cryosurgery. Each kidney was treated with two freeze cycles to -180 degrees C. Six kidneys were retroperitonealized, and six were not. An abdominal CT scan was performed at various times to evaluate for the presence of urinoma or hematoma and to monitor lesion changes. Organs were harvested at times ranging from 24 hours to 13 weeks. Radiographic and histopathologic changes were recorded for each time period. Eight patients with small (average 2-cm) exophytic renal masses underwent laparoscopic biopsy and cryosurgical ablation using a 3- or 4.8-mm probe (Cryomedical Sciences Inc., Rockville, MD) for one 15-minute or two 5-minute freeze cycles to a temperature of -180 degrees C to extend the ice ball at least 7 mm beyond the tumor margin. RESULTS: Dense adhesions between the bowel and cryoablated renal tissue were encountered in all non-retroperitonealized kidneys, but no fistula formation was present. The retroperitonealized kidneys had minimal adhesion formation. None of the animals developed a urinary fistula. At 24 hours and 1 week, CT scanning demonstrated an enhancement defect corresponding to the region of the ice ball with no urinoma or hematoma. At 13 weeks, only a nonenhancing cortical defect was seen. At immediate harvest, hemorrhage was noted in the area of the ice ball with a sharp demarcation at the edge of the freeze zone. At 1 week, four distinct zones were seen: central necrosis, inflammatory infiltrate, hemorrhage, and fibrosis with regeneration. At 13 weeks, the necrotic tissue had been replaced with a circumscribed area of fibrosis. There were no intraoperative or postoperative complications in the eight patients. The estimated blood loss was 140 mL, and the mean hospital stay was 3.5 days. At a mean clinical follow-up of 7.7 (range 1-18) months and radiographic follow-up of 5 months; there have been no tumor recurrences or significant changes in the serum creatinine concentration. At 24 hours, there was an enhancement defect in the area of the ice ball. The CT images at 13 weeks showed a nonenhancing cortical defect in the area of the ice ball. CONCLUSIONS: Cryosurgery can be readily delivered laparoscopically, creating a discrete lesion at the time of treatment that appears to be consistent over time. In the animal studies, complete tissue necrosis developed in the freeze zone, followed by reabsorption, and by 13 weeks, fibrous tissue had replaced the defect. In the animal and human trials, there were no operative complications, urinomas, hematomas, or bowel or urinary fistulas. Follow-up imaging in human trials revealed a persistent nonenhancing defect in the area of the freeze zone. Long-term clinical follow-up will be necessary to determine the cancer-free survival rate.
Aged↗
Chronic effect of pneumoperitoneum on renal histology.
BACKGROUND AND OBJECTIVE: Transient intraoperative oliguria is a constant phenomenon during laparoscopic procedures. Laboratory studies have demonstrated that this effect is secondary to a decrease in renal blood flow caused by the pneumoperitoneum. With the advent of laparoscopic harvest of the kidney for renal transplantation, a concern is that increased intra-abdominal pressure may compound the effect of acute cold and warm renal ischemia during transplantation. Acute transient renal ischemia can produce chronic sclerosing histopathologic changes in native kidneys which are similar to those seen in chronic allograft rejection. The effect of positive-pressure abdominal pneumoperitoneum (15 mm Hg) on native kidneys was examined using a rodent model. The effects on renal function and histologic features were also studied. MATERIALS AND METHODS: Twenty-four Harlan Wistar-Furth rats were divided into four groups: controls, 1-hour pneumoperitoneum-91-day survival, 5-hour pneumoperitoneum-91-day survival, and 5-hour pneumoperitoneum-7-day survival. Control animals underwent placement of the Veress needle and anesthesia but no induction of pneumoperitoneum. At the time of sacrifice, blood was sampled for serum creatinine measurement. Both kidneys were harvested for frozen and permanent section and stained using hematoxylin and eosin. Specimens were graded for inflammatory and ischemic/sclerotic changes in the interstitium, tubules, glomeruli, and vasculature by a renal pathologist using a histologic score (0-3). RESULTS: In all groups, at a sacrifice interval of either 1 week or 3 months, there were no statistical differences in the histologic score, serum creatinine concentration, or renal weight. CONCLUSIONS: In a rodent model, no signs of chronic ischemic histologic changes were detected for a period of 3 months after up to 5 hours of pneumoperitoneum. As well, there was no change in the serum creatinine concentration.
Animals↗
Familial calcium stone disease: TaqI polymorphism and the vitamin D receptor.
BACKGROUND AND OBJECTIVE: Calcium nephrolithiasis has a strong familial component. However, to date, no specific genetic abnormality has been identified. Allelic variation in the vitamin D receptor (VDR) gene has been suggested as a partial explanation of differential calcium absorption or excretion in these patients. Polymorphism of this gene has been associated with altered vitamin D activity and has been implicated in osteoporosis and prostate cancer. We propose that a similar association may be found between familial hypercalciuric stone disease and the VDR. SUBJECTS AND METHODS: Genomic DNA was isolated from 37 controls and 19 patients with hypercalciuria (> 250 mg/24 hours) and a family history of nephrolithiasis. A 740-basepair segment of the VDR gene was amplified by polymerase chain reaction, digested with TaqI endonuclease, and resolved by gel electrophoresis. Alleles were classified as "T" if only one TaqI site was present and "t" if two were present. A simplified strength of family history score (FHS) was computed by adding 2 and 1 points, respectively, for each first- and second-degree relative affected by stone disease. RESULTS: No difference in allelic or genotypic frequencies between the study and control groups was present. In the stone group, a significant association was found between the strength of the family history and the TT genotype. Patients with this genotype had an average FHS of 4.0, whereas the mean FHS for the Tt and tt genotypes was 2.0 and 1.8, respectively (P < 0.05). Nonsignificant trends of the TT genotype toward a higher number of stone episodes (19 v 13 and 3) and higher 24-hour urine calcium excretion (408 v 297 and 353 mg) were also noted in the study group. CONCLUSION: The results suggest that the TT genotype is associated with more aggressive stone disease, both within families and with respect to recurrence. Quantifying the risk of calcium stone disease through DNA markers has potential application in determining the risk of a patient's family members for nephrolithiasis or a patient's risk of recurrence. This information may have therapeutic implications with regard to the rigor of medical therapy and frequency of follow-up.
Alleles↗
Retroperitoneal access for transperitoneal laparoscopy in patients at high risk for intra-abdominal scarring.
BACKGROUND AND PURPOSE: Adhesions from prior extensive open abdominal surgery can make initial transperitoneal access for laparoscopy hazardous. An alternative to open port placement is a retroperitoneal approach to the peritoneal cavity. We describe our retroperitoneal access for transperitoneal laparoscopy and evaluate the success of the subsequent laparoscopic procedure. PATIENTS AND METHODS: Eight patients with a history of abdominal surgery have undergone retroperitoneal access to the peritoneum prior to a laparoscopic urologic procedure. With the patient in a lateral decubitus position, the retroperitoneum is entered with a 10-mm Visiport device (US Surgical Corp., Norwalk, CT) along the posterior axillary line. A working space is bluntly created, the peritoneum identified anterior to the colon, and the endoscope passed through a peritoneotomy. The abdomen is then inspected, transperitoneal ports are strategically placed under direct vision, and the intended procedure is commenced. RESULTS: In all cases, retroperitoneal access to the peritoneum and subsequent trocar placement was successful. In five cases, the intended procedure was completed laparoscopically. In a case of bilateral ureterolysis, one side was completed laparoscopically; however, the other required open conversion. In two nephrectomies for xanthogranulomatous pyelonephritis (XGP), open conversion was necessary because of fibrosis. CONCLUSION: Retroperitoneal access to the peritoneal cavity permits safe and effective port placement when previous abdominal surgery makes initial transabdominal access difficult. However, despite successful access, in patients at risk for extensive perinephric fibrosis (e.g., XGP), a high incidence of open conversion may be expected.
Abdomen↗
Laparoscopic genitourinary surgery utilizing 20 mm Hg intra-abdominal pressure.
Traditional practice has dictated that intra-abdominal pressure during laparoscopy be kept at or below 15 mm Hg to minimize the risk of cardiovascular and pulmonary complications. This study was undertaken to determine if maintaining an intra-abdominal pressure of 20 mm Hg could be utilized safely during genitourinary laparoscopy. We reviewed the intraoperative records of 76 consecutive patients undergoing various endoscopic urologic procedures at an intra-abdominal pressure of 20 mm Hg to assess physiologic changes and complications. The records were examined for operating time, minute ventilation (MV), end-tidal CO2 (ETCO2), and peak inspiratory pressure (PIP), which were compared with the preinsufflation values. Also, in the first 39 patients, initial insufflation volumes were recorded at 15 mm Hg and then again when pressure was raised to 20 mm Hg. The mean operating time was 186 +/- 90 min. There was an average 22% increase in the sufflated volume when the pressure was elevated from 15 to 20 mm Hg. To maintain a suitable ETCO2, the anesthesiologist needed to increase the MV an average of 2.9 +/- 2.0 L/min. Increases in ETCO2 (average 4.5 +/- 4.6 mm Hg) and PIP (6.9 +/- 3.6 mm Hg) were noted. In two cases, the intra-abdominal pressure had to be decreased from 20 to 15 mm Hg because of inability to maintain an acceptable ETCO2. Subcutaneous emphysema was noted in three patients, which resolved spontaneously within 24 hr. In one patient, asymptomatic pneumomediastinum was noted after a 6-hr procedure. Intra-abdominal insufflation can be safely maintained at 20 mm Hg in most patients. This higher pressure improves maintenance of the pneumoperitoneum.
Adult↗
The EndoHand: comparison with standard laparoscopic instrumentation.
Laparoscopic instrumentation is constantly being refined in an attempt to achieve the proficiency, flexibility, and tactile feedback that would be available if the human hand were small enough to be used in laparoscopic surgery. The EndoHand (DAUM GmbH, Schwerin, Germany) is a novel laparoscopic three-fingered hand developed as an advancement over standard laparoscopic tools. Grasping and manipulation ability, dexterity, and tactile feedback were compared with those of current laparoscopic instrumentation. Experiments included measurement of achievable angles of approach to a fixed point behind a 2-cm-tall obstruction, completion time and error rates during a pelvic trainer dexterity task, and tactile feedback using a device invented to simulate tissue resistance. Subjectively, the EndoHand was able to pick up a range of objects similar to those graspable by a Babcock clamp. More complex types of manipulation were possible with the EndoHand because of its wrist joint. The range of approach angles to the fixed point was 35 degrees to 90 degrees with the EndoHand and 70 degrees to 90 degrees with the straight instruments. The dexterity of the EndoHand was significantly less than that of the other two instruments, as measured by time (P = 0.0002) and errors (P = 0.02). Standard instruments were also more accurate in the tactile feedback trials (P = 0.02). The EndoHand is a prototype of a unique new generation of laparoscopic instruments. Although it falls short in both dexterity and tactile feedback, significant promise is shown in its ability to perform sophisticated manipulation of objects and its flexibility to work at a larger range of angles to the target tissue. The EndoHand may be most useful on the nondominant hand of the surgeon to assist with positioning and holding tissue in a specific orientation. Clinical trials will determine its eventual role in laparoscopic surgery.
Confidence Intervals↗
Laparoscopic live donor nephrectomy: the four year Johns Hopkins University experience.
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Humans↗
Laparoscopic versus open pyeloplasty: assessment of objective and subjective outcome.
PURPOSE: We determine the subjective and objective durability of laparoscopic versus open pyeloplasty. MATERIALS AND METHODS: From August 1993 to April 1997, 42 patients underwent laparoscopic pyeloplasty (laparoscopy group) with a minimum clinical followup of 12 months (mean 22). Subjective outcomes and objective findings were compared to those of 35 patients who underwent open pyeloplasty (open surgery group) from August 1986 to April 1997 with a minimum clinical followup of 12 months (mean 58). We assessed clinical outcome based on responses to a subjective analog pain and activity scale. In addition, radiographic outcome was assessed based on the results of the most recent radiographic study. RESULTS: Of the 42 laparoscopy group patients 90% (38) were pain-free (26, 62%) or had significant improvement in flank pain (12, 29%) after surgery. Two patients had only minor improvement and 2 had no improvement in pain. Surgery failed in only 1 patient with complete obstruction. A patent ureteropelvic junction was demonstrated in 98% (41 of 42 patients) of the laparoscopy group on the most recent radiographic study (mean radiographic followup 15 months). Of the 35 open surgery group patients 91% were pain-free (21, 60%) or significantly improved (11, 31%) after surgery. One patient had only minor improvement and 2 were worse. CONCLUSIONS: Pain relief, improved activity level and relief of obstruction outcomes are equivalent for laparoscopic and open pyeloplasty.
Adolescent↗
Laparoscopic testicular denervation for chronic orchalgia.
PURPOSE: No specific cause is identified in most cases of chronic orchialgia. Nonsurgical therapies, including management at a chronic pain clinic, are generally recommended. Only when multiple conservative measures fail are patients offered surgical intervention, such as orchiectomy. We evaluate laparoscopic testicular denervation as an organ preserving and minimally invasive surgical alternative. MATERIALS AND METHODS: Since 1993, 9 patients with chronic orchialgia have undergone transperitoneal laparoscopic testicular denervation after nonsurgical modalities failed. Using 1, 10 mm. and 1 or 2, 5 mm. ports, the gonadal vessels were isolated circumferentially and divided cephalad to the vas deferens and its vasculature. Preoperative treatment modalities, morbidity and outcome were documented. A cord block provided temporary relief in all 9 patients. Analog scales were used to assess long-term pain relief (0 no pain to 100 worst pain) and activity levels (0 bedrest to 100 no restrictions). RESULTS: Average symptom duration before laparoscopic testicular denervation was 4.1 years. Of 9 patients 8 had undergone prior scrotal surgery. Failed nonsurgical modalities included anti-inflammatory drugs in 7 patients, antibiotics in 6, pain clinic consultations in 4 and antidepressant medications in 2. Mean pain score decreased from 69.4 (range 35 to 90) preoperatively to 30.6 at a mean followup of 25.1 months. Excluding the 2 cases that had no pain relief (less than 10-point reduction), average pain score decreased from 69 to 19 postoperatively (mean reduction 71%). Activity levels improved in all cases. There were no significant complications, including testis atrophy. One patient who had no pain relief underwent subsequent hydrocelectomy for pain, which also failed. CONCLUSIONS: Laparoscopic testicular denervation can provide significant long-term pain relief and appears to be a reasonable alternative in select cases with chronic orchialgia refractory to medical therapy. Larger series and prospective evaluations are necessary.
Adult↗
Stone entrapment during percutaneous removal of infection stones from a continent diversion.
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Humans↗
Laparoscopic donor nephrectomy: standard of care or unnecessary risk of organ loss?
Laparoscopic donor nephrectomy was developed to remove disincentives to live donation. It has been demonstrated to decrease the length of hospitalization, postoperative pain, time to convalescence and activity, while providing an optimal cosmetic result. Initial reports suggest that laparoscopic donor nephrectomy is feasible and equivalent to open donor nephrectomy.
Humans↗
Clinical decision making using teleradiology in urology.
OBJECTIVE: Using a personal computer-based teleradiology system, we compared accuracy, confidence, and diagnostic ability in the interpretation of digitized radiographs to determine if teleradiology-imported studies convey sufficient information to make relevant clinical decisions involving urology. Variables of diagnostic accuracy, confidence, image quality, interpretation, and the impact of clinical decisions made after viewing digitized radiographs were compared with those of original radiographs. MATERIALS AND METHODS: We evaluated 956 radiographs that included 94 IV pyelograms, four voiding cystourethrograms, and two nephrostograms. The radiographs were digitized and transferred over an Ethernet network to a remote personal computer-based viewing station. The digitized images were viewed by urologists and graded according to confidence in making a diagnosis, image quality, diagnostic difficulty, clinical management based on the image itself, and brief patient history. The hard-copy radiographs were then interpreted immediately afterward, and diagnostic decisions were reassessed. All analog radiographs were reviewed by an attending radiologist. RESULTS: Ninety-seven percent of the decisions made from the digitized radiographs did not change after reviewing conventional radiographs of the same case. When comparing the variables of clinical confidence, quality of the film on the teleradiology system versus analog films, and diagnostic difficulty, we found no statistical difference (p > .05) between the two techniques. Overall accuracy in interpreting the digitized images on the teleradiology system was 88% by urologists compared with that of the attending radiologist's interpretation of the analog radiographs. However, urologists detected findings on five (5%) analog radiographs that had been previously unreported by the radiologist. CONCLUSION: Viewing radiographs transmitted to a personal computer-based viewing station is an appropriate means of reviewing films with sufficient quality on which to base clinical decisions. Our focus was whether decisions made after viewing the transmitted radiographs would change after viewing the hard-copy images of the same case. In 97% of the cases, the decision did not change. In those cases in which management was altered, recommendation of further imaging studies was the most common factor.
Decision Making↗
Laparoscopic live donor nephrectomy: debating the benefits. Pro: similar costs to traditional surgery and procedure wins donors.
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Costs and Cost Analysis↗
Telemedicine and surgical robotics: urologic applications.
Medical treatment can be improved through integration and application of advances in technology, computers, and engineering. Accuracy and reliability are essential characteristics of any mechanical system, and with the evolution of machines capable of precise movements, the integration of medicine and machine is achievable. Early mechanical devices were effective in performing simple, repetitive tasks but were not sophisticated enough for independent function. In the automobile industry, robots could work on the assembly line executing these cyclic tasks. These machines could execute simple, reiterative movements without integrating new information from the environment. In this day and age, robots have evolved into sophisticated mechanical devices that can "react" to data detected in the environment to determine the next course of events. They have evolved from the assembly line to the operating room, assisting surgeons during surgery to participating in remote telesurgical procedures.
Journal Article↗
Laparoscopic live donor nephrectomy: technical considerations and allograft vascular length.
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Humans↗